WO2022027742A1

WO2022027742A1 - Integrated air-cooled axial flux motor

Info

Publication number: WO2022027742A1
Application number: PCT/CN2020/111209
Authority: WO
Inventors: 范兴纲; 李大伟; 曲荣海; 刘京易
Original assignee: 华中科技大学
Priority date: 2020-08-03
Filing date: 2020-08-26
Publication date: 2022-02-10
Also published as: CN111864966B; CN111864966A

Abstract

Disclosed is an integrated air-cooled axial flux motor, belonging to the technical field of motor cooling. Obliquely arranged blades are provided on a motor housing connecting a front rotor and a rear rotor. An air inlet is provided on the rotor disc of the front rotor and/or the rear rotor. A stator comprises a stator support, multiple supporting columns are symmetrically provided at two axial ends of the stator support and are arranged radially in a radiation pattern, and the multiple supporting columns form multiple U-shaped openings along the circumferential direction. The supporting columns at two ends are connected by means of a circumferential bottom, and the circumferential bottom is provided with ventilation ports and circumferentially arranged heat dissipation ribs. Stator cores wound with stator coils are embedded in the U-shaped openings. Rotor steel magnets have an oblique pole structure. U-shaped heat pipes are also provided on the stator cores. One end of each U-shaped heat pipe is inserted into the stator core in the axial direction, the other end of each U-shaped heat pipe is located on a circumferential outer surface of the stator core and is in close contact with the stator coil, and the stator core and the U-shaped heat pipe are integrally formed. The present invention effectively reduces temperature of the winding and the iron core in the axial flux motor, and improves thermal performance of the motor.

Description

An integrated air-cooled axial flux motor

【Technical field】

The invention belongs to the technical field of motor cooling, and more particularly, relates to an integrated air-cooled axial flux motor.

【Background technique】

Axial flux permanent magnet motor has attracted extensive attention and research by scholars at home and abroad due to its flat and compact structure and high power (torque) density. As a potential high power (torque) density motor topology, the shaft The flux motor has good application prospects in the fields of aerospace, ship propulsion, electric vehicles, etc. where the weight and space are limited.

In the axial flux motor, the single stator and double rotor yokeless armature separation type (YASA type, Yokeless and Segmented Armature) axial flux motor saves the stator yoke, the stator iron loss is small, and the armature winding coil It has received a lot of attention for reasons such as modular winding, and there are many related research results. Because of its large power density advantage and good market application prospects, some research institutions directly set up related companies to integrate innovative products. The research results are used for product transformation and promotion, and have won a good reputation in the global high-end motor market. Examples include Oxford University and YASA in the UK, Ghent University in Belgium and MagnaX.

However, the axial flux motor is difficult to cool due to its compact structure, especially the YASA structure motor. Since the stator has no yoke, the heat flow channel of the winding is reduced, which leads to the difficulty of heat dissipation of the motor winding. Therefore, an efficient winding cooling method is designed to reduce the winding temperature. It is of great significance to improve the power and torque of the motor to improve the thermal performance of the motor.

[Content of the invention]

In view of the defects and improvement requirements of the prior art, the present invention provides an integrated air-cooled axial flux motor, the purpose of which is to effectively reduce the winding temperature in the axial flux motor to improve the thermal performance of the motor.

In order to achieve the above purpose, the present invention provides an integrated air-cooled axial flux motor, comprising a front rotor, a stator and a rear rotor arranged coaxially in sequence, an air gap is formed between the stator and the two rotors, and the front rotor is and the rear rotor include rotor disc, rotor core and magnetic steel, among which,

The front rotor and the rear rotor are connected by a casing, and the casing is provided with blades arranged obliquely; the rotor disk of the front rotor and/or the rear rotor is provided with an air inlet;

The stator includes a stator support, a stator core and a stator coil;

The axial ends of the stator support are symmetrically arranged with a plurality of support columns radially arranged in a radial shape, and the plurality of support columns form a plurality of U-shaped grooves along the circumferential direction; the support columns at both ends are connected through the circumferential bottom, and the circumferential bottom There is a ventilation opening on it;

There are a plurality of stator iron cores, the stator coils are wound on the stator iron cores, and the stator iron cores wound with the stator coils are respectively embedded in a U-shaped slot.

The integrated air-cooled axial flux motor provided by the present invention has obliquely arranged blades on the casing connecting the front and rear rotors, an air inlet is arranged on the rotor disk, and an air outlet is arranged on the stator support, so that the stator and the rotor are arranged with an air inlet. The air gap between the rotors and the stator coils form a cooling flow channel; during operation, under the action of the rotation of the casing, the cooling air will enter the motor through the air inlet located on the rotor disk; after the cooling air enters the motor, part of the cooling air It flows through the air gap between the rotor disk and the stator, and after cooling the surface of the magnetic steel and the stator core, it flows out through the blade gap on the casing; part of the cooling air flows through the stator through the ventilation openings on the axial bottom supported by the stator. Between the coils, after cooling the stator coil, it flows out through the blade gap on the casing; during this process, the cooling air is directly in full contact with the magnetic steel, the stator core and the stator coil, which can directly and efficiently conduct the axial flux motor. cooling, effectively improving the thermal performance of the motor.

In the present invention, after winding the stator coil on the stator iron core, the stator iron core can be embedded in the corresponding stator slot, the stator coil is easy to assemble, and the stator coil is easy to fix.

Further, the magnetic steel on the front rotor and/or the rear rotor adopts a slanted pole structure.

In the integrated air-cooled axial flux motor provided by the present invention, the magnetic steel on the front rotor and/or the rear rotor adopts a slanted pole structure, so that the rotor can act as a centrifugal fan to generate a certain air volume during the rotation process, thereby Strengthen the cooling effect of the motor.

Further, circumferentially arranged cooling ribs are also provided on the circumferential bottom of the stator support.

In the integrated air-cooled axial flux motor provided by the present invention, cooling ribs are arranged on the circumferential bottom of the stator support, and after the support columns at both ends of the stator support conduct the heat generated by the stator coils to the bottom of the stator support, they are arranged on the bottom of the stator support. The heat dissipation ribs at the bottom will further conduct heat to the cooling air to enhance the cooling effect on the stator coils; in addition, the heat dissipation ribs are arranged in the circumferential direction at the circumferential bottom of the stator support, which can strengthen the strength of the stator support.

Further, the heat dissipation ribs on the circumferential bottom are arranged in multiple rows along the circumference of different radii, thereby improving the heat conduction capability and enhancing the cooling effect.

Further, a U-shaped heat pipe is also arranged on the stator core wound with the stator coil;

One end of the U-shaped heat pipe is inserted into the stator core along the axial direction, and the other end is located on the outer circumferential surface of the stator core and is closely attached to the stator coil.

In the present invention, a U-shaped heat pipe is arranged on the stator iron core, and one end of the U-shaped heat pipe inserted into the stator iron core in the axial direction can absorb the heat inside the stator iron core, and conduct to the end of the U-shaped heat pipe located on the outer surface of the stator iron core to dissipate heat, At the same time, the end of the U-shaped heat pipe located on the outer surface of the stator core can also directly dissipate heat to the stator coil that is close to it, thereby effectively improving the cooling effect of the stator core and the stator coil.

Further, the U-shaped heat pipe is located on one end of the outer circumferential surface of the stator core, and a plurality of external cooling fins are arranged in the axial direction, so that the heat dissipation of the U-shaped heat pipe located at one end of the outer circumferential surface of the stator core can be enhanced. ability.

Further, the U-shaped heat pipe is axially inserted into one end of the stator core, and a plurality of radially arranged internal heat absorbing fins are arranged, thereby enhancing the heat absorption capability of the U-shaped heat pipe axially inserted into one end of the stator core.

Further, the stator core is made of soft magnetic composite material (SMC), so that the insertion hole on the stator core for inserting the U-shaped heat pipe can be easily processed.

Further, the stator core and the U-shaped heat pipe are integrally formed, which facilitates the processing of the insertion hole on the stator core for inserting the U-shaped heat pipe, and effectively reduces the number of stator cores and U-shaped heat pipes made of soft magnetic composite materials. The contact thermal resistance between them improves the heat dissipation of the stator core.

Further, on the circumferential bottom of the stator support, each ventilation port is arranged in the axial middle position between the two axially symmetrical support columns, thereby facilitating the circulation of cooling air between the stator coils and strengthening the ventilation of the stator coils. cooling effect.

In general, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

(1) The integrated air-cooled axial flux motor provided by the present invention has obliquely arranged blades on the casing connecting the front and rear rotors, an air inlet is arranged on the rotor disk, and a vent is arranged on the stator support, so that the The air gap between the stator and the rotor, as well as between the stator coils, form a cooling flow channel; during operation, under the action of the rotation of the casing, the cooling air will enter the motor through the air inlet located on the rotor disk, and directly interact with the magnetic steel, The stator iron core and the stator coil are in full contact, which can directly and efficiently cool the axial flux motor and effectively improve the thermal performance of the motor.

(2) In the integrated air-cooled axial flux motor provided by the present invention, the magnetic steel on the front rotor and/or the rear rotor adopts a slanted pole structure, which can enhance the cooling effect of the motor.

(3) In the integrated air-cooled axial flux motor provided by the present invention, heat dissipation ribs are arranged on the circumferential bottom of the stator support, which can enhance the cooling effect of the stator coil and strengthen the strength of the stator support. In a preferred solution of the present invention, the heat dissipation ribs on the circumferential bottom are arranged in multiple rows along the circumference of different radii, thereby improving the heat conduction capability and enhancing the cooling effect.

(4) In the integrated air-cooled axial flux motor provided by the present invention, a U-shaped heat pipe is arranged on the stator iron core, which can absorb the heat inside the stator iron core and conduct it to the outside for dissipation, and dissipate heat to the stator coil, thereby Effectively improve the cooling effect of the stator core and the stator coil. In a preferred solution of the present invention, the U-shaped heat pipe is located on one end of the outer circumferential surface of the stator core, and a plurality of external cooling fins are arranged in the axial direction, so that the U-shaped heat pipe can be strengthened to be located on the outer circumferential surface of the stator core. The heat dissipation capacity of one end of the surface; the U-shaped heat pipe is inserted into one end of the stator core in the axial direction, and a plurality of radially arranged internal heat-absorbing fins are arranged, so that the absorption of the U-shaped heat pipe at one end of the stator core in the axial direction can be strengthened. thermal capacity.

(5) In the preferred solution of the integrated air-cooled axial flux motor provided by the present invention, the stator core is made of soft magnetic composite material (SMC), which can facilitate the processing of the stator core for inserting U-shaped The socket for the heat pipe; the stator core and the U-shaped heat pipe are processed by integral molding, which can facilitate the processing of the socket on the stator core for inserting the U-shaped heat pipe, and effectively reduce the number of the stator core and the U-shaped heat pipe made of soft magnetic composite materials. The contact thermal resistance between the type heat pipes improves the heat dissipation of the stator core.

(6) In the integrated air-cooled axial flux motor provided by the present invention, after the stator coil is wound around the stator core, the stator core can be embedded in the corresponding stator slot, the stator coil is easy to assemble, and the stator is easy to install. The coil is fixed.

(7) The integrated air-cooled axial flux motor provided by the present invention realizes the air-cooling of the motor through the integrated fan blades of the casing or the self-ventilation of the inclined pole of the rotor, which simplifies the system structure of the air-cooled motor and reduces the size of the system. size, weight and cost.

【Description of drawings】

1 is a three-dimensional exploded view of an integrated air-cooled axial flux motor provided by an embodiment of the present invention;

2 is a longitudinal cross-sectional view of an integrated air-cooled axial flux motor provided by an embodiment of the present invention;

3 is a schematic structural diagram of a motor rotor provided by an embodiment of the present invention;

4 is a schematic structural diagram of a casing provided by an embodiment of the present invention;

5 is a schematic diagram of a stator support structure provided by an embodiment of the present invention;

FIG. 6 is a schematic diagram of a stator coil assembly provided by an embodiment of the present invention;

7 is a schematic diagram of a U-shaped heat pipe provided by an embodiment of the present invention;

8 is a schematic diagram of a motor cooling air flow path according to an embodiment of the present invention;

Throughout the drawings, the same reference numbers are used to refer to the same elements or structures, wherein:

1 is the front rotor, 11 is the rotor disc of the front rotor, 12 is the rotor core of the front rotor, 13 is the magnetic steel of the front rotor, 14 is the front bearing, 15 is the magnetic steel platen of the front rotor, 2 is the stator, 21 is the stator Support, 211 is a support column, 212 is a heat dissipation rib, 22 is a stator core, 221 is an internal heat sink socket, 23 is a stator coil, 24 is a U-shaped heat pipe, 241 is an external heat sink, 242 is an internal heat sink, 25 is the fixing screw, 26 is the stator bar, 3 is the rear rotor, 31 is the rotor disc of the rear rotor, 32 is the rotor core of the rear rotor, 33 is the magnetic steel of the rear rotor, 34 is the rear bearing, and 35 is the magnetic steel of the rear rotor. Steel plate, 4 is the casing, 41 is the blade, 5 is the air inlet, 6 is the first cooling channel, 7 is the second cooling channel, 8 is the third cooling channel, and 9 is the air outlet.

【detailed description】

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

In the present invention, the terms "first", "second" and the like (if present) in the present invention and the accompanying drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

The axial flux motors involved in the following embodiments are all axial flux motors with a single-stator and double-rotor yokeless armature separation (YASA) structure.

Example 1:

An integrated air-cooled axial flux motor, as shown in Figures 1 and 2, includes: a front rotor 1, a stator 2 and a rear rotor 3 that are coaxially arranged in sequence, and air is formed between the stator 2 and the two rotors respectively. Air gap; as shown in FIG. 3, the front rotor 1 includes a rotor disk 11, a rotor core 12 and a magnetic steel 13, the rotor core 12 is mounted on the rotor disk 11, the magnetic steel 13 is mounted on the rotor core 12, and The structure of the rear rotor 3 is similar to that of the front rotor 1. Correspondingly, the rear rotor 3 includes a rotor disk 31, a rotor iron core 32 and a magnetic steel 33, and the rotor iron core 32 is installed and attached to the rotor disk 31. , the magnetic steel 33 is installed and attached to the rotor core 32, and is fixed by the magnetic steel pressing plate; the front rotor 1 and the rear rotor 3 and the stator 1 are supported by the front bearing 14 and the rear bearing 24 respectively, so as to facilitate the rotation movement; wherein,

The front rotor 1 and the rear rotor 3 are connected by a casing 4 to reduce the eccentricity and deformation of the two rotor disks; the casing 4 has blades 41 arranged obliquely. The structure of the casing 4 is shown in FIG. 4 , the blades 41 The inclination angle can be determined according to the actual motor structure and heat dissipation requirements to ensure the air volume and efficiency; the rotor disk 31 of the rear rotor 3 is provided with an air inlet 5;

The structure of the stator 2 is shown in FIG. 5 and FIG. 6 , including a stator support 21 , a stator core 22 and a stator coil 23 ;

The axial ends of the stator support 21 are symmetrically provided with a plurality of supporting columns 211 radially arranged in a radial shape, and the plurality of supporting columns 211 form a plurality of U-shaped grooves in the circumferential direction; the supporting columns 211 at both ends are connected by a circumferential bottom , There are ventilation openings on the bottom of the circumferential direction. In order to facilitate the circulation of cooling air, as an optional implementation, in this embodiment, each ventilation opening is arranged in the axial middle position between the two axially symmetrical support columns. ;

There are a plurality of stator cores 22, the stator coils 23 are wound on the stator cores 22, and the stator cores 22 wound with the stator coils 23 are respectively embedded in a U-shaped slot; in this embodiment, the special structure design of the stator support 21 , so that after the stator coil 23 is wound around the stator core 22, the stator core 22 can be embedded in the corresponding stator slot, the stator coil 23 is easy to assemble, and it is easy to fix the stator coil 23; The stator coil 23 and the stator iron core 22 are fixed and pressed by using the fixing screw 25 and the stator pressing bar 26;

In the integrated air-cooled axial flux motor provided in this embodiment, the casing 4 connecting the front and rear rotors has obliquely arranged blades 41 , the rotor disk 31 of the rear rotor 3 is provided with an air inlet 5 , and the stator support 21 is provided with an air inlet 5 . A vent is provided to form a cooling channel between the air gap between the stator and the rotor and between the stator coils; as shown in Figure 2, the cooling channel formed in the air gap between the rear rotor 3 and the stator 2 is The first cooling channel 6, the radial cooling channel between the stator coils 23 is the second cooling channel 7, and the cooling channel formed in the air gap between the front rotor 1 and the stator 2 is the third cooling channel 8 , the blade gap on the casing 4 also constitutes the air outlet 9;

During operation, under the rotation of the casing 4, the cooling air will enter the motor through the air inlet 4 located on the rotor disk 31; after the cooling air enters the motor, it is divided into three parts; a part of the cooling air flows through the first cooling channel 6. After cooling the magnetic steel 33 of the rear rotor 3 and the surface of the stator core 22, it flows out through the air outlet 9; a part of the cooling air flows through the second cooling channel 7, and after cooling the stator coil 23, it flows through the air outlet 9 outflow; a part of the cooling air flows through the third cooling channel 8, after cooling the surface of the magnetic steel 13 and the stator core 22 of the front rotor 1, it flows out through the air outlet 9; during the cooling process, the cooling air directly interacts with the magnetic steel, The stator iron core and the stator coil are in full contact, which can directly and efficiently cool the axial flux motor and effectively improve the thermal performance of the motor.

Optionally, in this embodiment, the magnetic steel on the front rotor 1 and/or the rear rotor 3 adopts a slanted pole structure, so that the rotor can act as a centrifugal fan to generate a certain amount of air during the rotation process to enhance the cooling of the motor. Effect.

In order to further enhance the cooling effect, as an optional embodiment, as shown in FIG. 5 , the circumferential bottom of the stator support 21 is further provided with circumferentially arranged heat dissipation ribs 212 , and the heat dissipation ribs 212 on the circumferential bottom extend along the The circles with different radii are arranged in multiple rows; after the support column 211 conducts the heat generated by the stator coil to the bottom of the stator support, the heat dissipation rib 212 arranged at the bottom will further conduct the heat to the cooling air to enhance the cooling effect of the stator coil 23 In addition, the heat dissipation ribs 212 are arranged in the circumferential direction at the circumferential bottom of the stator support 21, which can strengthen the strength of the stator support 21; the arrangement of multiple rows of heat dissipation ribs helps to improve the heat conduction ability and enhance the cooling effect.

In order to further enhance the cooling effect, as an optional embodiment, as shown in FIG. 6 and FIG. 7 , a U-shaped heat pipe 24 is also provided on the stator core wound with the stator coil;

One end of the U-shaped heat pipe 24 is inserted into the stator core 22 in the axial direction to absorb the heat inside the stator core. and the stator coil 23 to dissipate heat;

In order to further enhance the heat dissipation capability of the end of the U-shaped heat pipe 24 located on the outer circumferential surface of the stator core 22 and the heat absorption capability of the end of the U-shaped heat pipe 24 inserted into the stator core 22 in the axial direction, in this embodiment, the U-shaped heat pipe 24 On one end of the outer circumferential surface of the stator core 22, a plurality of external cooling fins 241 are arranged in the axial direction, and the U-shaped heat pipe 24 is inserted into one end of the stator core 22 in the axial direction. Internal heat absorbing sheet 242;

As shown in FIG. 7 , the stator core 22 is provided with corresponding inner heat absorbing fin insertion holes 221; in order to overcome the problem of difficult processing of the inner heat absorbing fin insertion holes 221 caused by the complex structure of the inner heat absorbing fins 242, as a kind of In the preferred embodiment, in this embodiment, the stator core 22 is made of soft magnetic composite material (SMC), and the U-shaped heat pipe 24 is directly formed and manufactured together with the SMC stator core. This method can also effectively reduce the cost of the SMC stator core. The contact thermal resistance with the U-shaped heat pipe improves the heat dissipation of the stator core;

Based on the above-mentioned optimized design of the stator structure, this embodiment can effectively reduce the temperature rise of the windings and improve the thermal performance of the motor. Specifically, the cooling air flow paths between the winding coils are shown in FIG. 8 .

The air-cooling method for the axial flux motor proposed in this embodiment has a compact structure and is deeply integrated with the mechanical support components of the motor and the electromagnetic structure. weight.

Example 2:

An integrated air-cooled axial flux motor, this embodiment is similar to the above-mentioned Embodiment 1, the difference is that in this embodiment, the air inlet is arranged on the front rotor;

For other structures and working principles of the motor, reference may be made to the description in Embodiment 1 above, which will not be repeated here.

Example 3:

An integrated air-cooled axial flux motor, this embodiment is similar to the above-mentioned Embodiment 1, the difference is that in this embodiment, both the front rotor and the rear rotor are provided with air inlets;

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be Included in the protection scope of the present invention.

Claims

An integrated air-cooled axial flux motor comprises a front rotor, a stator and a rear rotor arranged coaxially in sequence, an air gap is formed between the stator and the two rotors respectively, and the front rotor and the rear rotor both comprise a rotor disk, a rotor Iron cores and magnets, characterized in that,

The front rotor and the rear rotor are connected by a casing, and the casing is provided with blades arranged obliquely; the rotor disk of the front rotor and/or the rear rotor is provided with an air inlet;

The stator includes a stator support, a stator core and a stator coil;

The axial ends of the stator support are symmetrically arranged with a plurality of support columns radially arranged in a radial shape, and the plurality of support columns form a plurality of U-shaped grooves along the circumferential direction; the support columns at both ends are connected through the circumferential bottom, and the circumferential bottom There is a ventilation opening on it;

There are a plurality of stator iron cores, the stator coils are wound on the stator iron cores, and the stator iron cores wound with the stator coils are respectively embedded in a U-shaped slot.
The integrated air-cooled axial flux motor of claim 1, wherein the magnetic steel on the front rotor and/or the rear rotor adopts a slanted pole structure.
The integrated air-cooled axial flux motor according to claim 1 or 2, characterized in that the circumferential bottom of the stator support is further provided with circumferentially arranged cooling ribs.
The integrated air-cooled axial flux motor of claim 3, wherein the heat dissipation ribs on the circumferential bottom are arranged in multiple rows along the circumference of different radii.
The integrated air-cooled axial flux motor according to claim 1 or 2, characterized in that, a U-shaped heat pipe is also arranged on the stator core wound with the stator coil;

One end of the U-shaped heat pipe is inserted into the stator core along the axial direction, and the other end is located on the outer circumferential surface of the stator core and is closely attached to the stator coil.
The integrated air-cooled axial flux motor of claim 5, wherein the U-shaped heat pipe is located on one end of the outer circumferential surface of the stator core, and is provided with a plurality of external heat sinks arranged in the axial direction.
The integrated air-cooled axial flux motor of claim 5, wherein the U-shaped heat pipe is axially inserted into one end of the stator core, and is provided with a plurality of radially arranged internal heat absorbing fins.
The integrated air-cooled axial flux motor of claim 7, wherein the stator core is made of soft magnetic composite material.
The integrated air-cooled axial flux motor of claim 8, wherein the stator iron core and the U-shaped heat pipe are integrally formed.
The integrated air-cooled axial flux motor according to claim 1 or 2, characterized in that, on the circumferential bottom of the stator support, each vent is arranged at an axial middle position between two axially symmetrical support columns.